Documentation/4.0/Developers/Tutorials/ModuleWriting

For the latest Slicer documentation, visit the read-the-docs.

Consider also reading

• QtPortInSlicer - How to write a module
• How to write an external module

Initialization

1) Create the module directory

Use the module wizard to generate files and directory based on a template.

Linux	Mac	Windows
$ cd Slicer4 $ python Utilities/Scripts/ModuleWizard.py MY_MODULE_NAME	You need to open a terminal and go to the Slicer4 source directory. Start -> Microsoft Visual Studio 2008 -> Visual Studio Tools -> Visual Studio 2008 Command Prompt Then type in the terminal: $ cd path\to\Slicer4 $ ..\Slicer4-Superbuild\python-build\PCBuild\python.exe Utilities\Scripts\ModuleWizard.py MY_MODULE_NAME

Replace MY_MODULE_NAME with the name of the module you want (e.g. HelloWorld)
After running the script, a new directory MY_MODULE_NAME should be created in Slicer4/Modules/Loadable

2) Add the module in CMake

Edit the file Slicer4/Modules/Loadable/CMakeLists.txt: Add the name of your module at the end of the qtmodules variable assignment:

...
set(qtmodules
  ...
  MY_MODULE_NAME
  )
...

3) Compile

Compile the inner build (Slicer-build inside the Superbuild directory).

Linux	Mac	Windows
$ cd ../Slicer4-Superbuild/Slicer-build; $ make -j4	$ cd ..\Slicer4-Superbuild\Slicer-build; $ .\Slicer.exe --VisualStudio Slicer.sln In Visual Studio, go to Build -> Build Solution

4) Check the module

Start Slicer and make sure the module is present (listed under "Module Template")

$ ./Slicer

To change the module title that shows up in Slicer, edit the file Slicer4/Modules/Loadable/MY_MODULE_NAME/CMakeLists.txt

set(qt_module_title "Your title") 

Other properties for the module such as help, acknowledgment or categories can be re-implemented directly in C++ by editing Slicer4/Modules/Loadable/MY_MODULE_NAME/qSlicerMY_MODULE_NAME.cxx.

5) Open Qt Designer using the launcher

Slicer (the launcher) searches Qt Designer on your machine (using QT_QMAKE_EXECUTABLE set at configure time). It starts the designer after setting the correct environment variables (QT_PLUGIN_PATH for the widgets designer plugins and PATH/LD_LIBRARY_PATH for the libraries).

$ ./Slicer --designer

6) Change the UI

Using Qt Designer, edit the module UI file: Modules/Loadable/MY_MODULE_NAME/Resources/UI/qSlicerMY_MODULE_NAMEModule.ui
More info on how to use the designer

7) Edit the module files

Slicer4/Modules/Loadable/MY_MODULE_NAME/qSlicerMY_MODULE_NAME.[h|cxx]
Slicer4/Modules/Loadable/MY_MODULE_NAME/qSlicerMY_MODULE_NAMEWidget.[h|cxx]
Slicer4/Modules/Loadable/MY_MODULE_NAME/Logic/vtkSlicerMY_MODULE_NAMELogic.[h|cxx]
...

Qt Designer

• How to set icons to widgets
  • In the icon property entry of the widget (Property Editor), select a resource file
    • Slicer4/Modules/Loadable/MY_MODULE_NAME/Resources/qSlicerMY_MODULE_NAMEModule.qrc
    • Slicer4/Libs/MRML/Widgets/Resources/qMRMLWidget.qrc
    • Slicer4/Base/QTGUI/Resources/qSlicerBaseQTGUI.qrc
• How to add an icon in a resource file
  • Add the icon in Slicer4/Modules/Loadable/MY_MODULE_NAME/Resources/Icon
  • Edit the resource file by adding the line
    • "<file>Icons/MyIcon.png</file>"

Dependency between modules

It is possible that your module needs to access information from another module. Typically the logic of a module. The following code is an example of what can be done to make your module dependent to the Volumes module logic: In CMakeLists.txt:

 set(qt_module_include_directories
   ${CMAKE_CURRENT_SOURCE_DIR}/Widgets
   ${CMAKE_CURRENT_BINARY_DIR}/Widgets
   ${vtkSlicerVolumesModuleLogic_SOURCE_DIR}
   ${vtkSlicerVolumesModuleLogic_BINARY_DIR}
   )
  ... 
 set(qt_module_target_libraries
   ...
   vtkSlicerVolumesModuleLogic
   )

In qSlicerMY_MODULE_NAMEModule.cxx:

 QStringList qSlicerMY_MODULE_NAMEModule::dependencies()const
 {
 return QStringList() << "Volumes";
 }
 void qSlicerMY_MODULE_NAMEModule::setup()
 {
 this->Superclass::setup();

 vtkSlicerMY_MODULE_NAMELogic* moduleLogic =
   vtkSlicerMY_MODULE_NAMELogic::SafeDownCast(this->logic());

 qSlicerAbstractCoreModule* volumesModule =
   qSlicerCoreApplication::application()->moduleManager()->module("Volumes");
 if (volumesModule)
   {
   vtkSlicerVolumesLogic* volumesLogic = 
     vtkSlicerVolumesLogic::SafeDownCast(volumesModule->logic());
   moduleLogic->SetVolumesLogic(volumesLogic);
   }

By specifying the module as a dependency, you are insured that the dependency will be setup before your module is setup.

Follow the same pattern in CMakeLists.txt to add dependency on a module widgets:

set(qt_module_include_directories
  ... 
  ${qSlicerVolumesModuleWidgets_SOURCE_DIR}
  ${qSlicerVolumesModuleWidgets_BINARY_DIR}
  ...
  )
 ...
 set(qt_module_target_libraries
   ...
   qSlicerVolumesModuleWidgets
   )